Preparation of Cr17Mn11Mo3N powders by high-pressure gas atomization and the nitrogen increasing mechanism

Abstract High nitrogen-containing austenitic stainless steels (HNASSs) have been widely explored and developed due to their unique properties. Herein, the atmospheric/high-pressure melting and gas atomization technique was developed to successfully prepare different nitrogen-containing Cr17Mn11Mo3N powders. The size and nitrogen content of the powders can be tuned by controlling the atomization pressure or/and chamber pressure. Benefiting from the synergetic effect between atomization pressure and chamber pressure, nitrogen content can reach 0.402 wt% even without adding nitride alloys, and small median particle size, narrow powder size distribution and high yield of fine powders can be also achieved. Furthermore, the N origin and increasing mechanism were researched by comparative experiments. It reveals that the increase of nitrogen mainly derives from the melting process and the nitrogen mainly exists in form of dissolved state in steel matrix. This work will give a promising guidance for designing and fabricating the HNASS powders in future.